1. Field of the Invention
The present invention relates to a recording apparatus provided as a printer, a copying machine, a facsimile equipment, or the like, and to a recording apparatus used as the output equipment of complex type electronic equipment or a work station such as a computer, a word processor, or the like. More particularly, the invention relates to a recording apparatus provided with recording means for recording by use of color liquid (ink) on a recording material, which is a sheet material, and also, with discharging means for discharging a recording material from a recording area of the recording means.
2. Related Background Art
The recording apparatus provided with a printer, a copying machine, facsimile equipment, or the like, or the recording apparatus, which is used for output equipment of complex type electronic equipment or a work station such as a computer, a word processor, or the like is structured to perform recording images on a recording material (recording sheet), such as a paper sheet or thin plastic plate, in accordance with image information. The recording apparatus of the kind is classified by the recording method adopted therefor into ink jet type, wire-dot type, thermal type, laser beam type, among some others.
The serial scanning type recording apparatus adopts the serial scanning method of performing a main scan in the direction intersecting with the conveying direction of a recording material (sub-scanning direction), and has recording means mounted on a cartridge that travels along the recording material to record images (conducts main scanning). After one-line portion of recording is completed, a sheet feeding (pitch conveyance) in a designated amount is executed, and then, subsequently, images on the next line are recorded (main scanned) on the recording material that has come to a stop again. This operation is repeated to record entirely on the recording material.
On the other hand, for the recording apparatus of line type that records only by the sub-scanning in the conveying direction of a recording material, it is arranged to set a recording material on a designated recording position, and after recording a one-line portion altogether, a sheet feed in a designated amount (pitch conveyance) is conducted, and then, recording on the next line is performed altogether. This operation is repeated to record entirely on the recording material.
Of the recording apparatuses described above, a recording apparatus of ink jet type (ink jet recording apparatus) performs recording on a recording material by discharging ink from recording means (recording head), which makes it possible to make recording means compact, and to record images in high precision at high speed. Also, the recording apparatus of this type can record on a plain paper without giving any particular treatment, thus making the running costs lower. Also, because of non-impact type, it makes a lesser amount of noise with an advantage, among some others, that it can record color images with ease using ink of many colors. Of the ink jet recording apparatuses, a higher recording is possible by the line type apparatus, which uses recording means of line type where many discharge ports are arranged in the widthwise direction of a recording sheet.
FIGS. 7 to 9 are cross-sectional views that schematically Illustrate the structure around the recording area of the conventional ink jet recording apparatus. As shown in FIG. 7, the recording sheet P, which is fed by a sheet-feeding device (not shown), is nipped by a conveying roller 101 and a pinch roller 102, and conveyed to the recording area of the recording head 103, while the non-recording side thereof is being supported by a platen 106. The recording head 103 discharges ink to the recording sheet P for recording images on the recording sheet P. After images are recorded by the recording head 103, the recording sheet P is nipped by a sheet-discharging roller 104 and a spur 105, which are arranged on the downstream side in the conveying direction, and discharged by the rotations of the sheet-discharging roller 104 and the spur 105.
Now, it is assumed that a distance between the recording 103 and the recording sheet P is L. In an ink jet recording apparatus, the ink-jetted positions may delicately change depending on the distance between the recording head 103 and the recording sheet P. Therefore, if such distance is kept at a designated distance (L, for instance) all over the recording area, that is, if the recording sheet P can be placed along the platen 106 exactly, it should be possible to obtain images in high quality. Now, in the conventional ink jet recording apparatus, therefore, the rotational axis of the pinch roller 102 and the rotational axis of the spur 105 are often arranged to be offset more to the platen 106 side than the rotational axis of the conveying roller 101 and the rotational axis of the sheet-discharging roller 104 in order to place a recording sheet P along the platen 106 arranged on the lower side of the recording head 103.
Also, since the ink jet recording apparatus uses ink for recording, a recording sheet P is caused to expand when ink permeates the recording sheet P, and the recording surface of the recording sheet P waves (present cockling) on the recording area. Then, if the recording sheet P should float significantly from the platen 106 due to such cockling, not only do the positions of ink on the recording sheet deviate, but also, the recording surface is stained due to the recording head 103 that rubs the recording sheet P or the recording head 103 may be deteriorated or damaged if the recording head 103 collides with the edge portion of the recording sheet P.
Now, therefore, as shown in FIG. 8, the escapes 106xe2x80x2 and 104xe2x80x2 where a recording sheet P is made displaceable downward are provided for the platen 106 and the sheet-discharging roller 104 of the conventional ink jet recording apparatus, and also, the spur 107 is arranged to push the recording sheet P compulsorily into the escapes 106xe2x80x2 and 104xe2x80x2 of the platen 106 and the sheet-discharging roller 104. In this manner, the recording sheet P is allowed to wave downward regularly within the range of a designated height, hence preventing the recording sheet P from floating up.
However, when the leading end of the recording sheet P enters the spur 105 in the conventional structure as shown in FIG. 9, the leading end of the recording sheet P is pushed downward by the pushing-down spur 107. Because of reaction then, the recording sheet P on the recording area is caused to float up eventually (the condition indicated by solid line in FIG. 9) or the pushing-down spur 107 exerts resistance against the conveying force of the recording sheet P and buckles the recording sheet P, thus causing it to float up on the recording area eventually (the condition indicated by two-dot chain line in FIG. 9). Then, such defects as the degradation of recorded image, the deterioration of a recording head, or damages given thereto, may be invited in some cases.
As described above, the conventional recording apparatus is,provided with a pushing-down spur that pushes down a recording sheet compulsorily to a platen and the escape portion of a sheet-discharging roller in order to prevent the recording sheet from being cockled. However, when the leading end of the recording sheet enters the spur, the leading end of the recording sheet is pushed downward by the pushing-down spur, and by reaction exerted then, the recording sheet is caused to float up on the recording area or the pushing-down spur exerts resistance to the conveying force of the recording sheet to buckle the recording sheet, thus causing it to float up on the recording area eventually. As a result, there is a problem that may be encountered such as the degradation of recorded image, the deterioration of the recording head or damages given thereto.
It is an object of the present invention to provide a recording apparatus capable of high-quality recording on the entire area of a recording sheet even if the recording sheet expands by the permeation of ink
It is another object of the invention to provide a recording apparatus for recording on a sheet material by recording means, which comprises conveying means for conveying the sheet material to the recording area of recording means; a platen provided with plural extrusions for supporting the sheet material in the recording area, the plural extrusions being arranged in the direction intersecting with the conveying direction of the sheet material at designated intervals in a configuration of being extend in the conveying direction; plural sheet-discharging rollers for conveying a sheet material arranged on the downstream side of each of the extrusions in the conveying direction and in the same position as each of the extrusions in the intersecting direction: plural first spurs for nipping a sheet material with the plural sheet-discharging rollers for conveyance thereof by being driven to rotate following the plural sheet-discharging rollers; and a second spur arranged on the downstream side of the first spur in the conveying direction and between the plural sheet-discharging rollers in the intersecting direction, for rotating following the movement of a sheet material to push down the sheet material between the plural extrusions, the lowest part of the second spur being arranged to be lower than the uppermost part of the sheet-discharging roller when the sheet material does not abut thereupon.